1. Field of Inventions
The present inventions relate generally to apparatus and methods for charging the rechargeable batteries (and/or other rechargeable power sources) in implanted medical devices.
2. Description of the Related Art
A variety of power consuming medical devices may be implanted into a patient. Examples of such implantable medical devices include, but are not limited to, microstimulators (e.g. occipital nerve stimulators, vagus nerve stimulators, and stimulators that may be positioned at various locations to treat rheumatoid arthritis), implantable pulse generators, drug infusion pumps, speech processors, pacemakers and defibrillators. In addition to their therapeutic and/or diagnostic components, the implantable medical devices include rechargeable power sources such as rechargeable batteries, capacitors, and combinations thereof. The length of time that an implantable medical device can operate between chargings of the rechargeable power source varies from device to device. For example, pacemaker batteries may only need to be recharged every few years, while microstimulators (e.g. an occipital nerve stimulator) may need to be recharged several times a day.
The present inventors have determined that conventional methods and apparatus for charging the rechargeable power sources in implanted medical devices are susceptible to improvement. For example, the present inventors have determined that conventional methods and apparatus for charging the rechargeable power sources can involve the use of large and bulky chargers that are difficult to incorporate into daily life. The present inventors have also determined that it can be difficult to maintain the proper position of conventional chargers on the body relative to the implanted medical device.